U.S. patent number 4,721,473 [Application Number 06/932,072] was granted by the patent office on 1988-01-26 for retention feature for printed circuit board mounted connectors.
This patent grant is currently assigned to AMP Incorporated. Invention is credited to Henry L. DelGuidice, Roger J. Flaherty.
United States Patent |
4,721,473 |
DelGuidice , et al. |
January 26, 1988 |
**Please see images for:
( Certificate of Correction ) ** |
Retention feature for printed circuit board mounted connectors
Abstract
An electrical connector which has a plurality of electrical
contacts for interconnecting a plurality of data or communication
lines is mountable to a printed circuit board and interconnectable
to a plurality of electical traces thereon. The connector includes
a front mating portion which is connectable to a matable connector,
and a right angled portion, including a plurality of terminals, the
right angled portion being mountable to a printed circuit board and
the terminals being interconnectable to printed circuit board
through holes. The connector further comprises a retention member
which securely affixes the connector to the printed circuit board
prior to soldering of the connector to the printed circuit board,
and which provides a cylindrical soldering interface for mechanical
stability of the connector to the printed circuit board.
Inventors: |
DelGuidice; Henry L.
(Winston-Salem, NC), Flaherty; Roger J. (Greensboro,
NC) |
Assignee: |
AMP Incorporated (Harrisburg,
PA)
|
Family
ID: |
25461723 |
Appl.
No.: |
06/932,072 |
Filed: |
November 17, 1986 |
Current U.S.
Class: |
439/79; 439/569;
439/554; 411/508 |
Current CPC
Class: |
H01R
12/716 (20130101); H01R 12/00 (20130101); H01R
12/737 (20130101); H01R 12/724 (20130101); H01R
12/7029 (20130101) |
Current International
Class: |
H01R 009/09 () |
Field of
Search: |
;339/17R,17D,17C,17LC,14R,126R,126J,126RS,128,132R,132B,143T,193R
;411/32,33,508-510 ;439/79,80,92,554 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
AMP Specification Sheet, No. 938, revised 7-72. .
Addendum-FIGS. 1 and 2, Champ Shielded Connector, AMP Inc..
|
Primary Examiner: Abrams; Neil
Attorney, Agent or Firm: Groen; Eric J.
Claims
What is claimed is:
1. A retention member for retaining a shielded electrical connector
to a printed circuit board and for commoning said shielded
connector to a ground trace on said printed circuit board, the
connector having an insulative housing having a base portion which
is mountable to the printed circuit board and a front face portion
which is perpendicular to the base portion, the insulative housing
having at least one hole through the base portion of the housing,
the depth of said at least one hole being less than the thickness
of said base portion, the electrical connector further comprising a
front shielded portion which includes at least one commoning post
extending rearwardly through at least one aperture in the front
face portion of the insulative housing, the retention member
comprising:
a stamped and formed conductive member having a first plate portion
which is profiled to lie adjacent to the upper surface of the base
portion of said connector housing, said first plate portion having
two legs extending downwardly therefrom, each said leg portion
having a first and second retaining means, said first set of
retaining means being profiled to fit substantially adjacent to the
lower end of the hole in the base portion, and said second set of
retaining means being profiled to fit substantially adjacent to the
lower end of a through hole on said printed circuit board, and a
second plate portion profiled to overlie the aperture from the rear
thereof, said second plate portion include means to retain the
commoning post and the second plate portion together, thereby
affixing the shielded portion and the insulative housing together
and commoning the shielded portion to a ground trace on the printed
circuit board adjacent to the throughhole.
2. The retention member of claim 1 wherein the extending legs are
semi-cylindrically formed to face each other and form a
substantially cylindrial configuration.
3. The retention member of claim 2 wherein the extending legs
further comprise inwardly formed lead in sections which extend from
ends of the legs.
4. The retention member of claim 1 wherein the retention means are
outwardly formed deformations in the extending legs having an
arcuate cross section.
5. The retention member of claim 4 wherein the deformations are
dimple shaped.
6. The retention member of claim 4 wherein the arcuately shaped
deformations define upper and lower corners at the intersection of
the deformation with the extending leg, and an apex at the
furthermost deformed point.
7. The retention member of claim 6 wherein the second set arcuately
shaped deformations are profiled such that if the board is
undersized the end of the printed circuit board through hole is
located at the upper corner of the arcuately shaped
deformations.
8. The retention member of claim 6 wherein the second said
arcuately shaped deformations are profiled such that if the printed
circuit board is nominally sized or over sized, the end of the
printed circuit board through hole is below the upper corner of the
deformation but above the apex of the deformation.
9. The retention member of claim 1 wherein the retention member is
heat treated to increase the spring constant of the extending legs
thereby biasing the extending legs against the through hole on a
matable printed circuit board.
10. A shielded electrical connector for mounting to a printed
circuit board, interconnecting a plurality of electrical terminals
in the connector to a plurality of electrical traces on the printed
circuit board, the connector comprising:
a front shielded portion of a conductive material, the front
shielded portion having a front mating face profiled for receiving
a matable connector, an opening from the rear of the shielded
portion which extends to the front mating face, and commoning posts
extending from the rear of the shielded portion;
an insulative housing comprising a front portion and a base portion
for mounting the connector to the printed circuit board, the front
portion including apertures therethrough for receiving the
conductive posts of the front shielded portion, the base portion
having a mounting aperture means therethrough including a hole
having a depth which is less than the thickness of the base;
a plurality of terminals mounted within said housing having forward
portions which extend towards the front mating face of the shielded
portion for interconnection to a matable connector and right angled
portions which extend downwardly beyond the base portion for
interconnection to a printed circuit board;
at least one retention member for retaining the front shielded
portion to the insulative housing and for retaining the electrical
connector to a printed circuit board, the retention member
comprising a first plate means lying substantially adjacent to the
base means and a second plate means which upstands from the first
plate means having a profiled aperture for interferingly receiving
the conductive posts thereby retaining the front shielded portion
to the insulative housing, and two legs extending downwardly from
the first plate means, each said extending leg being
semi-cylindrically formed to face each other to form a
substantially cylindrical configuration, and each said extending
leg having first retention means to retain said connector to said
board.
11. The connector of claim 10 wherein the mounting aperture means
comprises a counterbored hole from an underside of said base
member.
12. The connector of claim 10 wherein the mounting aperture means
comprises standoff ribs extending along an underside of the base
thereby placing an end of the hole above the surface of a mountable
printed circuit board.
13. The connector of claim 10 further comprising second retention
means to retain the retention member to the connector base
portion.
14. The connector of claim 13 wherein the first and second
retention means are outwardly formed deformations arcuately
shaped.
15. The connector of claim 10 wherein the connector housing
includes channel means therethrough for receiving the commoning
means and placing them in biasing registration with the retention
member.
16. A shielded electrical connector which is mountable to a panel
and which interconnects a plurality of terminals to a printed
circuit board, the connector comprising:
a shielded connector piston which is mountable to the panel from a
first side, the shielded portion comprising means for latching the
shielded connector portion to the panel, the shielded connector
portion further comprising an opening therethrough which is
profiled for mounting over an opening in the panel, the shielded
connector portion further comprising at least one commoning arm
extending through the panel to a second side of the panel;
an insulative connector comprising means to house a plurality of
terminals, the insulative connector portion having a forward
portion profiled to extend into the opening in the shielded
connector portion, the terminals comprising first portions disposed
in the forward portion of the insulative connector portion for
interconnecting to a matable electrical connector and second
portions for interconnecting to the printed circuit board; and
retention tab means of conductive material mounted on the
insulative housing having means projecting through said printed
circuit board for commoning the commoning arm to a ground trace of
said printed circuit board, whereby,
when the insulative connector is placed against the second side of
the panel, the forward portion of the insulative housing projects
through the opening in the shielded connector portion which
disposes the first terminal portions forward of the first side of
the panel, and the at least one commoning arm is disposed against
the retention tab means which commons the shield to the retention
tab means.
17. The connector of claim 16 wherein the retention tab means
includes a stamped and formed plate and the means for commoning the
commoning arm to a circuit board trace comprises at least one leg
integral with the plate which is profiled for extending through a
printed circuit board through hole.
18. The connector of claim 17 wherein the insulative housing
includes a channel integral with the housing which extends behind
the plate of the retention tab means such that when the shielded
connector portion and the insulative connector piston are mated,
the commoning arms are located within said channels and resiliently
biased against the plate of the commoning tab.
19. The connector of claim 18 wherein the shielded connector piston
is molded from plastic material and plated with a conductive
material.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The subject invention relates to an electrical connector for
mounting to a printed circuit board and for interconnecting to the
electrical traces thereon, and more specifically to the retention
feature which mounts the electrical connector to the printed
circuit board.
2. Description of the Prior Art
There exists within the electronics industry electrical connectors
which are right angled mounted to printed circuit boards, and for
electrical interconnection to circuit traces on the printed circuit
boards. One such problem involved in this industry relates to the
mounting of the electrical connectors to the printed circuit
boards. Typically, the electrical connectors are robotically
inserted onto the printed circuit boards, and the assembly of the
board and the connector is transferred to a wave soldering line
where the electrical connector is soldered to the board. In
addition to the terminals of the connector being interconnected to
the printed circuit board, it is typical for a conductive retention
feature to be commoned to the shield of the connector and then
inserted into a through hole of the printed circuit board and
soldered to a ground trace on the board.
In such an application where the retention feature is to common the
shield to the printed circuit board, two considerations much be
addressed. First, the retention feature must hold the connector
squarely to the printed circuit board, in other words, the base of
the connector must be held firmly to the printed circuit board such
that the connector cannot rock on the printed circuit board. This
assures that when the assembly of the printed circuit board and the
connector are soldered to one another, the connector interface is
parallel to the board. Typically, the datum line for electrical
interconnections is the printed circuit board, thus a connector
which is not properly aligned with the printed circuit board could
actually preclude matability with the connector. For example, if
the printed circuit board is interconnected to a right angled
connector which is to mount within a personal computer, and the
connector is to abut an outside wall of the chassis, if the
connector is not properly aligned with the printed circuit board,
when the printed circuit board is interconnected within the
computer, the connector may not properly align with its intended
connection port. This could result in a cable with a connector
attached thereto which is not matable with the connector, or if it
is matable, the connector must be forcibly aligned with the port
which puts undue stresses on the printed circuit board
connections.
Another aspect which is important for retention features is that
they must provide adequate surface area for solderable
interconnection thereto. When the retention feature projects
through the printed circuit board through hole, the soldering of
the retention member to the board provides the mechanical and
electrical connection of the board to the connector. Increasing the
surface area on the retention members to which the printed circuit
board can be soldered, results in the strongest solder joint.
One such retention feature which is available is known as the split
arrow and includes a flat stamping having members which are bent
upwardly to form a flat locking feature which is parallel to the
board. One problem with the split arrow approach is that since the
locking member is flat or parallel to the board, the tolerance
buildups between the connectors, boards and retention members can
allow "play" between the connector housing and the board. This play
can allow the connector to rock when the connector is placed on the
board, such that when the board is soldered to connector, the
connector and board are not parallel, resulting in the
aforementioned problems.
The split arrow approach to board retention, as it is a flat
stamping, allows little surface area for soldering thereto. The
strength of a solder joint relates to the amount of solder
deposited and the surface area of the solder interface. The solder
interface on the split arrow retention feature is limited to the
thickness of the flat metal stamping. When the mechanical stability
of the connection system is limited to the strength of the solder
joint, the electrical integrity of the interconnection can be
jeopardized. For example, and again referring to the personal
computer, if the connector and printed circuit board are placed at
a port for exterior interconnection thereto, and the only
mechanical stability is provided by the solder joints, the stepping
on a cable which interconnects the printed circuit board mounted
connector to the printer could disrupt the electrical integrity of
the system.
SUMMARY OF THE INVENTION
The instant invention relates to an improved retention feature for
printed circuit board mounting and to an electrical connector
incorporating the same. The retention member is for use with an
electrical connector which is printed circuit board mounted. The
connector has an insulative housing with at least one hole through
a base portion of the housing which lies adjacent to the printed
circuit board. The depth of the hole is less than the thickness of
the base portion. The retention member is a stamped and formed
conductive member which has a first plate portion profiled to lie
adjacent to the base portion of the connector housing, where the
first plate portion has two legs extending downwardly therefrom.
Each leg portion includes a first and second retaining means where
the first set of retaining means is profiled to fit substantially
adjacent to the end of the hole in the base portion, and the second
set of retaining means is profiled to fit substantially adjacent to
the end of a through hole on a mountable printed circuit board.
A shielded electrical connector which incorporates the retention
member includes a front shielded portion having a front mating face
profiled for receiving a matable connector and an opening from the
rear of the shielded portion which extends to the front mating
face. The shielded portion further includes commoning means which
extend from the rear of the shielded portion. The shielded
electrical connector further includes an insulative housing which
includes a front portion and a base portion for mounting the
connector to the printed circuit board, where the insulative
housing is connectable to the front shielded portion. The base
portion of the insulative housing has a mounting aperture means
including a hole having a depth which is less than the thickness of
the base. The electrical connector further includes a plurality of
terminals which are mounted within the housing having four portions
which extend toward the front mating face of the shielded portion
for interconnection to a matable connector and right angled
portions which extend downwardly beyond the base portion for
interconnection to a printed circuit board. The leg portions of the
retention member extend through the mounting aperture means to
retain the connector to the printed circuit board while at the same
time the retention member and the front shielded portion are
cooperatively profiled such that the commoning means on the front
shielded portion and the retention member are commoned
together.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the connector and retention feature
of the preferred embodiment of the instant invention.
FIG. 2 is a perspective view of the retention member.
FIG. 3A is a cross sectional view through lines 3--3 of FIG. 1,
showing the printed circuit board exploded away from the
connector.
FIG. 3B is a view similar to that of FIG. 3A showing the position
of the retention member when the printed circuit board is of
optimal thickness.
FIG. 3C is a view similar to that of FIG. 3A showing the position
of the retention member when the printed circuit board is slightly
oversized.
FIG. 3D is a view similar to that of FIG. 3A showing the position
of the retention feature when the printed circuit board is slightly
undersized.
FIG. 4 is a perspective view of a second connector utilizing the
retention member.
FIG. 5 is a perspective view of the assembled connector of FIG.
4.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIG. 1, the subject invention relates to an
electrical connector for interconnecting to a printed circuit board
and which is matable to a complementary connector of the type
generally shown in U.S. Pat. No. 3,760,335, the disclosure of which
is incorporated herein by reference. The electrical connector 2 is
of the type shown in U.S. Pat. No. 4,469,387, the disclosure of
which is incorporated herein by reference.
The electrical connector 2 comprises an insulative housing portion
4 and a front mating portion 6 which, in the preferred embodiment
of the invention, is a shielded member. The preferred shield
portion 6 is a die cast material, although a shielded portion
manufactured from a drawn method could also be used. The shielded
portion 6 includes a plate member 26 having a metallic boss 28
which extends through the insulative housing 4. Retention members
40 interferingly fit over the shielded boss members 28 to hold the
housing member 4 and the shielded member 26 together. The connector
2 further comprises a plurality of terminals 30 having an end
disposed for interconnection to a printed circuit board and another
end disposed in the front shielded portion 6 for interconnection to
a matable electrical connector. Bail clips 32 hold the matable
electrical connector in a mating electrical condition.
Referring now to FIG. 2, the retention member 40 is shown in better
detail. Retention member 40 is a stamped and formed member
originally in the plane of plate member 50. The retention member 40
includes a right angled plate member 42 formed upwardly of the
original plane. The plate 42 includes an interfering spring
retention member 44 having individual spring edges 46. The
retention member 40 further includes two semi-cylindrical members
52 profiled to be received in a printed circuit through hole with
an outward resilient bias. The preferred embodiment of the
invention includes a retention member stamped and formed from 1050
steel and heat treated to stiffen the semi-cylindrical members 52,
thereby increasing the spring constant of the members 52. The
semi-cylindrical members 52 include first outwardly facing dimples
54 and a second set of outwardly facing dimples 56. As best shown
in FIG. 2, extending from the bottom of the semi-cylindrical
members 52 are two lead-in portions 58.
On each side of the connector housing 4 is located a mounting plate
8 (FIG. 1) for receiving the retention members 40. Referring now to
FIG. 3A, the mounting plate 8 is shown in better detail. Each
mounting plate 8 includes a counterbored hole 10 from the underside
surface 18 of the plate 8. The counterbored hole 10 is defined by a
first diameter 12 and a second diameter 16, which defines a
downwardly facing shoulder 14. The retention members 40 are
inserted through the upper surface 20 of the plate member 8 such
that the first dimple 54 just clears the downwardly facing shoulder
14, as shown in FIG. 3A. As the manufacturing tolerances of the
housing 4 and the retention member 40 are controllable, the
distances between surfaces 14 and 20 of the mounting plate 8, and
the distance between the underside surfaces 60 of the retention
member and the corner 64 of the dimple 54 can be held, such that
the optimum position for the retention member 40 is shown in FIG.
3A where the corner 22 of the counterbore 10 resides in the corner
64 of the first dimple 54.
The connector 2 is interconnectable to a printed circuit board 70
having a plated through hole 72 interconnected to a ground trace 74
as shown in FIG. 3A. The height of the plate through holes 72
cannot be closely toleranced however, and the height of most
printed circuit board through holes varies from plus to minus 0.005
inches. In an attempt to retain the connectors to the printed
circuit boards given any variance in printed circuit through hole
thickness, the second set of dimples is controlled such that the
optimum condition, that is where the printed circuit board
thickness is plus 0.000 inches and minus 0.000 inches, the corner
76 of the plated through hole is slightly below the corner 62 of
the dimples 56, as best shown in FIG. 3B. Therefore, when the
thickness of the plated through hole or the printed circuit board
70 decreases to minus 0.005 inches the corner 76 of the plated
through hole will be in the corner 62 of the dimples 56, as shown
in FIG. 3D. If the thickness of the printed circuit board and the
plated through hole increases to the plus 0.005 inch dimension, the
vertical distance from the corner 76 of the plated through hole
with respect to the corner 62 of the dimples 56 will be
approximately 0.010 inches, however the corner will still reside on
the dimple above the apex of the dimple 56.
Thus, irrespective of the variance in printed circuit board
thickness, the resultant resilient force from the spring biased
retention members 52 will still include an upward component applied
to the printed circuit board through hole 72 from the underside,
clamping the printed circuit board 70 and the under surface 18 of
the housing plate 8 together. This is especially important when
using a die cast shielded portion as the connector tends to be
"nose heavy." This is also extremely important when the connector
and printed circuit board assembly is robotically transferred to a
soldering line, where in the transferring, the connector could be
disengaged from the printed circuit board.
In order to reduce the insertion force of the retention members 40
into the printed circuit board through holes 72, as shown in FIG.
4, each leg member 52 includes an inwardly formed foot portion 58.
The inwardly shaped foot portion 58 in combination with the
spherically shaped dimples 56 reduces the insertion force of the
retention members into the printed circuit board. Furthermore, the
spherically shaped dimples 56 prevent scuffing or scratching the
plated through hole 72 while it is being inserted. Furthermore, if
prior to the soldering of the connector to the printed circuit
board 70, the connector must be removed, the spherically shaped
dimples 56 allow the easy removal of the connector from the printed
circuit board, without degrading the electrical characteristics of
the plated through hole 72.
In the first embodiment of the electrical connector, the shield
portion 6 includes a conuctive post 28 extending rearwardly from
the conductive plate 26. The conductive post extends through the
housing portion 4 such that the spring member 44 (FIG. 2) overlies
the conductive post and locks the shielded portion 6 and the
housing portion 4 together. When the connector 2 is mounted to a
printed circuit board in one of the configurations shown in FIGS.
3B-3D, the extending leg portions extend through the through hole
to dispose the extending leg 52 in registration with the through
hole 72 to common the shield 6 to the ground trace 74.
After the connector 2 is placed on the printed circuit board 70,
the connector and board as an assenbly is transferred to a wave
soldering line where the connector 2 and board 70 are soldered
together. The larger the interface of the retention member 40 for
soldering thereto, the stronger the solder joint. As shown in FIG.
2, the retention members 40 include semi-cylindrical portions 52
which, when inserted into the printed circuit board through hole
72, give the maximum amount of surface area to which the solder can
adhere. When the retention member 40 is inserted through the
printed circuit board through hole 72, as designed, the solder
interface on the retention legs 52 is close to 180.degree..
As shown in FIG. 4, the retention member 40 can also be used on a
panel mounted electrical connector 102 which is more fully
described in co-pending application Ser. No. 932,073, filed
concurrently herewith, the disclosure of which is incorporated
herein by reference. The panel mount connector 102 comprises a
forward matable portion 106 which is mountable to the outside of a
panel 200 (FIG. 5), such as a chassis of a personal computer. The
panel mount portion 106 includes resilient latches 138 to retain
the panel mount portion 106 to the panel 200, as shown in FIG. 5.
The connector portion 104 is insertable from the opposite side of
the panel 200 into an opening 107 and is held fixed against the
back side of the panel 200 by means of latches 132 engaging in
channels 136. As it is desirable to remove the connector portion
104 from the panel mount portion 106, while maintaining the panel
mount portion 106 in place, it is not desirable to use the spring
member 44 as used in the previous embodiment, that is to lock the
shielded portion and the housing portion together. It still is,
however, desirable to common the shielded panel mount portion 106
to the ground trace 74 via the retention member 40. As shown in
FIGS. 4 and 5, the plate portion 42 of the retention member 40 is
disposed to abut a channel 140 in the sides of the housing.
Extending from the back side of the panel mount portion 106 are two
commoning arms 128 having lead-in surfaces 132. The preferred
embodiment of the connector 102 comprises a plated plastic shielded
portion 106 and an insulative member 104. Thus as the connector
portion 104 and the panel mount portion 106 are assembled, as shown
in FIG. 5, the conductive commoning arms 128 are disposed in
channels 140 and are resiliently biased against the plate portion
42 of the retention member 40. In this manner, the forward shielded
portion can be grounded to the ground trace on the printed circuit
board. The plate member 108 of the housing portion 104 is similarly
configured to the embodiment shown in FIGS. 1 through 4 such that
the retention member 40 is insertable through the aperture 116 in
the plate 108 and the first dimple 54 resides just below the
surface 114 of the plate member 108. Surface 118 of the plate
member 108 is similarly configured to the first embodiment such
that the dimples 56 accommodate the printed circuit board as in
FIGS. 3A through 3D.
The description of the invention was made with respect to specific
references to the Figures, but should not be taken to limit the
claims which follow.
* * * * *